A number of light-emitting layer structures for the GaN-based LEDs that can increase the lighting efficiency of the GaN-based LEDs on one hand and facilitate the growth of epitaxial layer with better quality on the other hand are provided. The light-emitting layer structure provided is located between the n-type GaN contact layer and the p-type GaN contact layer. Sequentially stacked on top of the n-type GaN contact layer is the light-emitting layer containing a lower barrier layer, at least one intermediate layer, and an upper barrier layer. That is, the light-emitting layer contains at least one intermediate layer interposed between the upper and lower barrier layers. When there are multiple intermediate layers inside the light-emitting layer, there is an intermediate barrier layer interposed between every two immediately adjacent intermediate layers.